6-aminocarbonyl purine 3&#39;,5&#39;-cyclic nucleotides

ABSTRACT

N 6  -Carbamoyl and -carbonyl analogs of adenosine 3&#39;,5&#39;-cyclic phosphate (cAMP) are prepared and variously demonstrated to exhibit kinase, adrenal steroidogenisis and lipolysis activation superior to cAMP, inhibit phosphodiesterase, and found to increase cardiac output or, in particular cases, to lower blood pressure.

BACKGROUND AND BRIEF SUMMARY OF THE INVENTION

Numerous N⁶ - carbamoyl and -carbonyl purines have been prepared, eg,Giner-Sorolla et al, J. Am. Chem. Soc. 80, 3932 (1958) and A. S. Joneset al, Tetrahedron Letters 26,791 (1970). The ureidopurinesN-(purin-6-ylcarbamoyl) threonine, N-(purin-6-ylmethylcarbamoyl)threonine and N(purin-6-ylcarbamoyl) glycine have been found to occurnaturally as their riboside in tRNA. See G. B. Chedda et al, Biochem. 8,3278 (1969), M. P. Schweizer et al, ibid.,8, 3283 (1969). M. P.Schweizer et al, ibid., 40, 1046 (1970) and H. Ishikura, Biochem.Biophys. Res. Commun. 37, 90 (1969). N-(purin-6-ylcarbamoyl) threoninehas also been identified in human urine. G. B. Chedda, Life Sci. 8, 979(1969). Several ureidopurine derivatives related toN-(purin-6-ylcarbamoyl) threonine have been synthesized and found tohave cytokinin like growth-promoting properties. See C. I. Hong et al,J. Med. Chem. 16, 139 (1973) and R. H. Hall et al, Cancer Res. 31, 704(1971). C. I. Hong et al, Abstracts, 162d Am. Chem. Soc. Nat'l. Meeting,Wash. D.C. (Sept 1971) have prepared 5'-phosphates of a number ofnaturally occuring 6-ureidopurine nucleosides, including those ofstructure ##STR1## wherein R was alkyl or aryl. Adenosine 3', 5'-cyclicphosphate (cAMP, 1) has been well established as a mediator of manyhormonal effects, and numerous of its 8-substituted derivatives havebeen prepared and demonstrated to possess physiological activity. Eg,U.S. Pat. No. 3,712,885 to Weimann et al.

According to this invention, there are prepared novel cyclic nucleotidesof structure ##STR2## wherein Y is COOR₁, CONHR₁ or CONHC₆ H₅, X isacyl, H or Y, Z is H, halogen or SR₂, R₁ is C₁ - C₆ alkyl and R₂ is H,phenyl, benzyl or C₁ - C₆ alkyl. The manner in which these compoundswith the advantage of their properties previously referred to areobtained will appear from the detailed description which follows.

DETAILED DESCRIPTION OF THE INVENTION

N-alkyl and N-phenyl-N⁶, 2'-O-bis-carbamoyladenosine 3',5'-cyclicphosphates (eg, 2, 3 and 4) are prepared by treatment of cAMP (1) withcorresponding alkyl or phenyl isocyanates at, eg, 60°-80° C. Selectivedeblocking with refluxing NaOCH₃ or aqueous NaOH at room temperatureaffords the corresponding N⁶ -carbamoyl adenosine 3',5'-cyclicphosphates (eg, 5, 6 and 7). The latter compounds may alternatively besecured, without intermediate formation of the N⁶,2'-O-bis-carbamoyladenosine nucleotide, by acyl blocking of the 2'-Oposition of 1 prior to reaction with isocyanate, followed by deblockingduring workup. Thus, for example, phenylisocyanate and2'-O-acetyladenosine 3',5'-cyclic phosphate (9) afford thecorrespondingly 2'-O-acyl blocked N-phenyl-N⁶ -carbamoyladenosine cyclicnucleotide 10 and, following workup, the deblocked nucleotide 7.

Treatment of 1 with an appropriately chosen alkylchloroformate (eg,ethylchloroformate for N⁶ -ethoxycarbonyl-cAMP, 8) followed by treatmentwith 2 N NaOH affords the N⁶ -alkoxycarbonyl-cAMP derivatives.

8-Benzylthio-N⁶,2'-O-bis-(N-pheylcarbamoyl)-cAMP (12) is afforded bydirect treatment of 8-benzylthio-cAMP [K. Muneyama et al, Biochem. 10,2390 (1971)] with phenylisocyanate, and basic hydrolysis affords8-benzylthio-N⁶ -(N-phenylcarbamoyl)-cAMP (15). The corresponding8-phenyl compounds are analogously obtained. Corresponding N⁶-(N-alkylcarbamoyl) compounds are obtained simply by appropriate choiceof isocyanate reactant.

8-Halogenated cAMP compounds (eg, 8-bromo-cAMP, K. Muneyama et al,Biochem. 10, 2390 (1971) and 8-chloro-cAMP, Robins et al, U.S. Pat.application Ser. No. 153,413 (filed June 15, 1971 and now abandoned)whose disclosure is incorporated herein by reference) afford access,through initial formation of 8-halo-N⁶ -mono- and N⁶,2'-O-bis-(N-alkyl-,N-phenyl-, carbamoyl)-cAMP derivatives, to otherwise 8-substituted N⁶-mono- and N⁶,2'-O-bis-(n-alkyl-, N-phenyl-, carbamoyl)-cAMP derivativesby nucleophilic substitution of the 8-halo moiety. For example,treatment of 8-bromo-N⁶,2'-O-bis-(N-methyl carbamoyl)-cAMP (11) withthiourea affords 8-thio-N⁶,2'-O-bis-(N-methyl carbamoyl)-cAMP (16). The8-thio group can be alkylated with, eg, C₁ -C₆ alkyl halides to form8-alkylthio N⁶ -mono- and N⁶,2'-O-bis-(N-alkyl- or or N-phenyl-,carbamoyl)-cAMP compounds and, employing α-bromotoluene, alkylationaffords an alternative route to 8-benzylthio analogs such as 12 and 15.

2'-O-acylated N-alkyl- and N-phenyl-carbamoyl cyclic nucleotides areuseful intermediates (eg, compound 10) and bioactive end products can besimilarly acylated to enhance lipid solubility, etc. The O-acylated (eg,C₁ -C₁₈ acyl) analogs may be secured by reacting the free nucleotideswith corresponding acid anhydrides or acyl halides (eg, acetyl, butyryl,hexanoyl, lauryl, adamantoyl, etc.). Sutherland et al, in Biochim. etBiophys. Acta 148, 106 (1967) have demonstrated that acylation enhancescellular transport of purine nucleotides. Especially preferred are the2'-O-butyryl derivatives prepared by reacting free nucleoside andbutyric anhydride at room temperature in dimethyl formamide:4-dimethylaminopyridine.

In the Examples of preferred embodiments which follow, evaporations wereperformed under diminished pressure at less than 40° C. The structuresof carbamoyl and carbonyl derivatives of cAMP were verified by pmr, uvspectra and elemental analysis, the latter analysis results lying within±0.3% of theoretical values where reported by reference to elementaldesignation (e.g., "C,H,N"). UV spectra were determined on a Cary 15spectrometer. Silica gel for column chromatography was E. M. ReagentSilica Gel 60 (particle size 0.063-0.200 nm). The eluates from columnchromatography were monitored at 254 nm to detect the presence of uvabsorbing compounds. All samples were dried over CaSO₄ at 100° underhigh vacuum. All temperatures are in ° C.

EXAMPLE 1 N⁶, 2'-O-bis-(N-Methylcarbamoyl)adenosine 3',5'-cyclicphosphate sodium salt (2).

A solution of 1.0 g (3.2 mmole) of cAMP (1), 1 ml Et₃ N and 3 mlmethylisocyanate in 50 ml of DMF was heated at 80° overnight in a bomb.The solution was poured into 200 ml of Et₂ O and the Et₂ O decanted fromthe oil. The oil was again titurated with Et₂ O and decanted. Theresidue was dissolved in CHCl₃ and placed onto a 30 g column (2.5 cm D.)of silica gel (packed in CHCl₃). The column was washed with CHCl₃ andthen eluted with MeOH:CHCl₃ (15:85). The appropriate fractions werepooled and taken to dryness in vacuo. The residue was dissolved in H₂ Oand passed through a 50 ml column of Dowex 50 (Na⁺) resin. The columnwas eluted with H₂ O and the eluate was taken to dryness in vacuo andthe residue dissolved in MeOH. Two volumes of EtOH were added at boiland the volume reduced until solid started separating out. Thesuspension was cooled and the solid filtered and dried to yield 412 mg(28%) of 2; λ_(max) ^(pH) 1 276 nm (ε 23,100), λ_(max) ^(pH) 7 267 nm,280 sh (ε 22,500, 21,500), λ_(max) ^(pH) 11 267 nm, 280 sh (ε 21,900,18,600). Anal. (C₁₄ H₁₇ N₇ O₈ NaP) C, H, N, Na.

EXAMPLE 2 N⁶, 2'-O-bis-(N-Propylcarbamoyl)adenosine 3', 5'-cyclicphosphate sodium salt (3).

A solution of 7 g (21.3 mmole) of cAMP, 5 ml Et₃ N and 14 mlpropylisocyanate in 80 ml of DMF was heated in a bomb at 70° overnight.The solvent was removed in vacuo and the residue co-distilled with H₂ Oand then EtOH. The final residue was taken up in CHCl₃ and placed onto acolumn (2.5 cm D.) of 70 g of silica gel (packed in CHCl₃). The columnwas eluted with CHCl₃ to remove the urea and then with Me0H: CHCl₃(1:9). The fractions containing product were pooled and reduced todryness in vacuo. The residue was dissolved in a small volume of H₂ Oand passed through a 4 × 15 cm column of Dowex 50 (Na⁺) resin. Thecolumn was eluted with H₂ O and the eluate reduced to dryness in vacuo.The residue was co-distilled with MeOH to dryness. The final residue wasdissolved in a small volume of Me0H and 5 volumes of EtOAc added. Thesolid was filtered, washed with EtOAc, washed with Et₂ O, and dried toyield 5.8 g (52%) of 3; λ_(max) ^(pH1) 276 nm (ε 24,900), (ε24,900),λ_(max) ^(pH7) 267 nm, 275 sh (ε 23,500, 20,100),λ_(max) ^(pH11)267 nm, 275 sh (ε 23,500, 20,100). Anal. (C₁₈ H₂₅ N₇ O₈ NaP.H₂ O) C, H,N, Na.

EXAMPLE 3 N⁶, 2'-O-bis-(N-Phenylcarbamoyl)adenosine 3',5'-cyclicphosphate sodium salt (4).

A solution of 12.0 g 36.5 mmole) of cAMP (1), 10 ml Et₃ N and 25 mlphenylisocyanate in 400 ml DMF was stirred overnight in a 70° oil bath.The resulting solution was concentrated to 1/2 in vacuo and thenpartitioned between 200 ml of H₂ O and 200 ml of EtOAc. The aqueousphase was heated on a steam bath and the hot solution extracted fourtimes with EtOAc. The final aqueous phase was warmed on a steam bath, 50ml of a saturated NaCl solution was added, and the solution was cooled.The resulting crystals were filtered, washed with a small amount of coldH₂ O and recrystallized from an H₂ O:EtOH (1:4) mixture. The final solidwas filtered, washed with EtOH and dried to yield 10 g (47%) of 4;λ_(max) ^(pH) 1 284 nm (ε 20,300), λ_(max) ^(pH) 7 231 nm, 276 (ε18,200, 22,100). λ_(max) ^(pH) 11 233 nm, 276 (ε 17,200, 21,500),λ_(max) ^(pH) 13 307 nm (ε 29,100). Anal. (C₂₄ H₂₁ N₇ O₈ NaP) C, H, N,Na.

EXAMPLE 4 N⁶ -(N-Methylcarbamoyl) adenosine 3',5'-cyclic phosphate (5).

A solution of 5.0 g (15.2 mmole) of cAMP (1), 5 ml of Et₃ N and 10 ml ofmethylisocyanate in 50 ml of DMF was heated at 60° overnight in a bomb.The solvent was removed in vacuo and the residue co-distilled once withMeOH and then dissolved in 200 ml of MeOH containing 5 g of NaOMe. Afterrefluxing for 8 hr, the solvent was removed in vacuo and the residuedissolved in H₂ O. This solution was placed onto a column (4 cm D.) of54 ml of Dowex 1 × 2(formate, 100-200 mesh). The column was washed withH₂ O and then eluted with a gradient of 800 ml of H₂ O in the mixingchamber and 800 ml of 6 N formic acid in the reservoir. Fractions of 25ml were collected. Fractions 36 to 60 were pooled, reduced to drynessand the residue co-distilled with EtOH. The final residue wasrecrystallized from EtOH to yield, after drying, 2.66 g (50%) of 5;λ_(max) ^(pH) 1 276 nm (ε 22,900), λ_(max) ^(pH) 7 267 nm, 275 sh (ε22,300, 19,000), λ_(max) ^(pH) 11 267 nm, 275 sh (ε 21,800, 18,500).Anal. (C₁₂ H₁₅ N₆ O₇ P.3/4H₂ O) C, H, N.

EXAMPLE 5 N⁶ -(N-Propylcarbamoyl) adenosine 3',5'-cyclic phosphate (6).

A solution of 2.6 g (5.0 mmole) of N⁶, 2'-O-(N-propylcarbamoyl)adenosine 3',5'-cyclic phosphate (3) and 3 g of NaOMe in 200 ml ofabsolute MeOH was refluxed for 9 hr. The solvent was removed and theresidue dissolved in a small volume of H₂ O and placed onto a 25 mlcolumn (2 cm D.) of Dowex 1 × 2 (formate, 100-200 mesh). The column waswashed with H₂ O and then eluted with a gradient of 350 ml of H₂ O inthe mixing chamber and 350 ml of 6 N formic acid in the reservoir.Elution was continued with 300 ml of 6 N formic acid. Fractions of 25 mlwere collected after start of gradient. Fractions 27 through 39 werepooled and taken to dryness in vacuo. The residue was co-distilled withMeOH twice, slurried in EtOH, filtered and dried to yield 1.06 g (51%)of 6; λ_(max) ^(pH) 1 277 nm (ε 23,800), λ_(max) ^(pH) 7 268 nm, 276 sh(ε 22,700, 19,200), λ_(max) ^(pH) 11 268 nm, 276 sh (ε 22,200, 18,900),λ.sub. max^(pH) 11 268 nm, 276 sh (ε 22,200, 18,900), λ_(max) ^(pH)12.65 277 nm, 296, 269 sh (ε 14,900, 16,600, 13,800). Anal. C₁₄ H₁₉ N₆O₇ P) C, H, N.

EXAMPLE 6A N⁶ -(N-Phenylcarbamoyl)adenosine 3',5'-cyclic phosphate (7).

Method A: A solution of 1.0 g (2.7 mmole) of 2'-O-acetyladenosine3',5'cyclic phosphate (9), 4 ml Et₃ N and 3 ml of phenylisocyanate in 50ml of DMF was stirred overnight at room temperature. The solution waspoured into 100 ml of H₂ O and stirred for 1/2 hr. The aqueous solutionwas extracted three times with 50 ml of Et₂ O and was reduced to drynessin vacuo. The residue was dissolved in 20 ml of 1 N NaOH and set asidefor 1/2 hr. The pH was then adjusted to 1 with 1 N HCl. The crystalswhich formed were filtered, washed with H₂ O and dried to yield 0.33 g(26%) of 7: λ_(max) ^(pH) 1 285 nm (ε 28,300), λ_(max) ^(pH) 277 nm (ε29,000), λ_(max) ^(pH) 11 277 nm (ε 28,600). Anal. (C₁₇ H₁₇ N₆ O₇P.1.5H₂ O) C, H, N.

EXAMPLE 6B N⁶ -(N-Phenylcarbamoyl) adenosine 3',5'cyclic phosphate (7).

Method B: A solution of 9.0 g (15.3 mmole) of N⁶,2'-O-bis(N-phenylcarbamoyl)adenosine 3',5'cyclic phosphate (4) in 75 mlof DMF and 45 ml of 2 N NaOH was stirred at room temperature for 2.5 hr.The solvent was removed in vacuo and the residue was partitioned between100 ml of H₂ O and 100 ml of Et₂ O. The aqueous phase was extractedthree times with Et₂ O and then was acidified to pH 1 with 1 N HCl. Theresulting solid was filtered, washed with H₂ O and dried to yield 6.2 g(85%) of 7.

EXAMPLE 7 N⁶ -(Ethoxycarbonyl)adenosine 3'5'-cyclic phosphate (8).

A hot solution of 6.0 g (18 mmole) of cAMP (1) and 5.2 of g of4-morpholine-N-N'-dicyclohexylcarboxamidine in aqueous pyridine wasco-distilled with pyridine to dryness. The residue was dissolved in 200ml of pyridine, cooled at 0° and 15 ml of ethylchloroformate was addeddropwise. The reaction mixture was allowed to warm to room temperatureovernight and then 50 g of ice was added. After 4 hr the solvent wasremoved in vacuo and the residue co-distilled with EtOH:toluene toremove traces of pyridine. The residue was taken up in H₂ O and the pHadjusted to 11 with 2 N NaOH. After 1/2 hr the solution was neutralizedwith AcOH, placed onto a 500 ml column (4 cm D.) of Dowex 50 × 8(H⁺¹⁰⁰⁻²⁰⁰ mesh) resin and eluted with H₂ O. The first fractions yieldedan impurity, followed by product and finally cAMP. The fractionscontaining the product were pooled, reduced in volume in vacuo andpassed through a 100 ml column of Dowex 50 (Na⁺) resin. The column waseluted with H₂ O and the eluate was reduced in vacuo to dryness. Theresidue was dissolved in boiling MeOH and two volumes of EtOH addedslowly at boil. The volume was reduced at boil until solid appeared.After cooling, the solid was filtered and dried to yield 2.15 g (28%) of8; λ_(max) ^(pH) 1 275 nm (ε 20,500, λ_(max) ^(pH) 7 267 nm (ε19,000),λ_(max) ^(pH) 11 268 nm, 289, 275 sh (ε 14,500, 9,500, 13,900).Anal. (C₁₃ H₁₅ N₅ O₈ NaP) C, H, N, Na.

EXAMPLE 8 8-Bromo-N⁶,2'-O-bis-(N-methylcarbamoyl)adenosine 3',5'-cyclicphosphate

A solution of 1 g (2.4 mmole) of 8-bromoadenosine 3',5'-cyclic phosphate(13)¹², 1, ml of Et₃ N and 2 ml methylisocyanate in 40 ml of DMF washeated at 70° overnight. After cooling to room temperature, the solutionwas partitioned between 150 ml of H₂ O and 150 ml of EtOAc. The aqueousphase was extracted three times with 150 ml of EtOAc and then placedonto a 17 ml column (2 cm D.) of Dowex 1 × 2 (formate, 100-200 mesh. Thecolumn was eluted with a gradient of 600 ml of H₂ O in the mixingchamber and 600 ml of 6 N formic acid in the reservoir. Three uvabsorbing peaks were eluted off of the column. The fractions of thethird peak were pooled and reduced to dryness in vacuo. The residue wasco-distilled twice with MeOH to give 550 mg of solid. An analyticalsample of the Na salt was prepared by passing 150 mg of the free acidthrough a 50 ml column of Dowex 50 (Na⁺). The column eluate was reducedto dryness in vacuo and the residue crystallized from EtOH and dried toyield 112 mg of 11; λ_(max) ^(pH) 1 281 nm, 291 sh (ε 21,800, 15,500),λ_(max) ^(pH) 7 277 nm, 280 (ε 22,400, 19,200), λ_(max) ^(pH) 11 277 nm,280 (ε 22,400, 19,200, λ_(max) ^(pH) 13 299 nm (ε 21,600). Anal. (C₁₄H₁₆ N₇ O₈ BrNap.H₂ O) C, H, N, Na.

EXAMPLE 9 8-Benzylthio-N⁶,2'-O-bis-(N-phenylcarbamoyl) adenosine3',5'-cyclic phosphate sodium salt (12).

A solution of 2 g (4.5 mmole) of 8-benzylthioadenosine 3',5'-cyclicphosphate sodium salt (14)¹² and 3ml phenylisocyanate in 50 ml of DMFwas heated at 70° overnight. The solution was partitioned between 150 mlof H₂ O and 150 ml of EtOAc. The aqueous phase was heated on a steambath and extracted twice with EtOAc while hot. The solid which separatedout of the cold aqueous phase was filtered and washed with a smallamount of cold H₂ O. The solid was recrystallized from EtOH and dried toyield 1.4 g (43%) of 12; λ_(max) ^(pH) 1 309 (ε 17,500), λ_(max) ^(pH) 7295 nm (ε 20,000), λ_(max) ^(pH) 11 298 nm (ε 24,800), λ_(max) ^(pH)12.8 321 nm (ε 31,000 ). Solutions of 12 were opaque and ε values aretherefore minimum values). Anal. (C₃₁ H₂₇ N₇ O₈ NaPS.1/2 H₂ O) C, H, N,Na, S.

EXAMPLE 10 8-Benzylthio-N⁶ -(N-phenylcarbamoyl)adenosine 3',5'-cyclicphosphate (15).

A solution of 0.6 g (0.83 mmole) 8-benzylthio-N⁶,2'-O-bis-(N-phenylcarbamoyl)adenosine 3',5'-cyclic phosphate sodium salt(12) in 6 ml of DMF and 4 ml 2 N NaOH was stirred at room temperaturefor 2.5 hr. The solvent was removed in vacuo and the residue waspartitioned between 50 ml of hot H₂ O and 50 ml of EtOAc. The hotaqueous phase was extracted two times with 50 ml of EtOAc. EtOH (50 ml)was added to the aqueous solution and the pH was adjusted to 2 with 1 NHCl. The gelatinous solid which formed was filtered, washed with 10 mlH₂ O and dissolved in 20 ml of EtOH. The solution volume was reduced to10 ml, cooled and the solid filtered and dried to yield 220 mg (45%) of15; λ_(max) ^(pH) 1 308 nm (ε 27,900), λ_(max) ^(pH) 7 296 nm (ε31,200), λ_(max) ^(pH) 11 296 nm (ε 31,200), λ_(max) ^(pH) 11 296 nm (ε30,300), λ_(max) ^(pH) 12.75 320 nm (ε 32,800). Anal. (C₂₄ H₂₃ N₆ O₇PS.H₂ O) C, H, N, S.

EXAMPLE 11 N⁶,2'-O-bis-(N-Methylcarbamoyl)-8-mercaptoadenosine3',5'-cyclic phosphate sodium salt (16).

A solution of 700 mg of N⁶,2'-O-bis-(N-methylcarbamoyl)-8-bromoadenosine3',5'-cyclic phosphate (11) and 700 mg of thiourea in 50 ml of H₂ Ocontaining 5 drops of formic acid was refluxed for 1 hr. After cooling,the pH was adjusted to 8.5 with 1 N NaOH. The solvent was distilled offin vacuo and 3 g of silica gel added to the residue. The residue wassuspended in MeOH and the MeOH evaporated in vacuo. The final residuewas added to a 15 g column (2.5 cm D.) of silica gel (packed in CHCl₃).The column was washed with CHCl₃ to remove thiourea and then the productwas eluted off with MeOH:CHCl₃ (1:3). The solvent was removed in vacuoand the residue suspended in EtOH, filtered and dried, yielding 300 mg(45%) of 16; λ_(max) ^(pH) 1 244 nm, 313 (ε 19,800, 33,800), λ_(max)^(pH) 7 233 nm, 312 (ε 17,800, 30,800, λ_(max) ^(pH) 11 233 nm, 311 (ε17,500, 29,600). Anal. (C₁₄ H₁₇ N₇ O₈ NaPS.13/4 H₂ O) C, H, N, S.

Preferred carbamoyl compounds prepared as in the preceding examples wereassayed for ability to activate protein kinase by the proceduredescribed in K. Muneyama et al, Biochem. 10, 2390 (1971), using bovinebrain C-AMP dependent kinase purified according to Kuo & Greengard, inProc. Nat. Acad. Sci. U.S.A. 64, 1349 (1969). Compounds 6, 7 and 15proved superior in kinase activation to C-AMP itself and, indeed,compound 7 activated bovine brain protein kinase approximately fivetimes better than C-AMP (Ka'=4.9, where Ka is the activation constantdetermined from a Line-weaver-Burk plot and Ka' = K_(a) for C-AMP/K_(a)for test compound). The highest value for Ka' previously reported in theliterature was 3.77, for the 8-thio derivative of C-AMP. K. Muneyama etal, supra.

When tested for vulnerability to degradation by rabbit kidney high K_(m)C-AMP phosphodiesterase according to the procedure of J. P. Miller etal, Biochem. 12, 1010 (1973), all of compounds 2, 3, 4, 5, 6, 7, 8, 11,12, 15 and 16 proved more resistant to hydrolysis than C-AMP. In fact,hydrolysis to any appreciable extent could be detected only in the caseof compound 8 (hydrolysis at a rate only 8% that of C-AMP).

Certain of the preferred compounds proved equal to or superior totheophylline as inhibitors of one or both of beef heart and rabbit lungphosphodiesterase in assay by the method of J. P. Miller et al, supra.The results appear in Table I below.

                  TABLE I                                                         ______________________________________                                        Inhibition of Beef Heart and Rabbit Lung                                      cAMP Phosphodiesterases                                                       ______________________________________                                                  I.sub.50 (μM)                                                    Compound    Beef Heart    Rabbit Lung                                         ______________________________________                                        11          260           130                                                  7          22            160                                                  4          93            190                                                 12          22             10                                                 15          14             21                                                  8          130           210                                                 Theophylline                                                                              130           230                                                 ______________________________________                                    

In addition to the foregoing, compounds 5, 6, 7 and 8 have been shown toactivate steroidogenisis and lipolysis at concentrations substantiallylower than C-AMP. Compounds 7, 15, and their 2'-O-butyryl derivativesinhibit adenyl cyclase, suggesting employment in treatment of choleraand as immunosuppressive or anti-inflammatory agents (see Shuman et alapplication Ser. No. 368,323, filed June 8, 1973, now U.S. Pat. No.3,853,303, the disclosure of which is incorporated herein by reference).Compounds 5, 6, 8 and 15 act to lower blood pressure, and compound 7 asan inotropic agent has proven persistent in action and the equal ofaminophylline in increasing cardiac output, without deleteriouslyaffecting heart rate.

We claim:
 1. A compound of structure ##STR3## wherein Y is COOR₁,CONHR₁, or CONHC₆ H₅, X is C₁ -C₁₈ acyl, Y or H, Z is H, bromine, orchlorine SR₂, R₁ is C₁ - C₆ alkyl and R₂ is H, phenyl, benzyl or C₁ - C₆alkyl.
 2. A compound according to claim 1 wherein X is acyl or H.
 3. Acompound according to claim 2 wherein Y is CONHR₁ or CONHC₆ H₅.
 4. Acompound according to claim 3 wherein Y is CONHC₆ H₅.
 5. N⁶-(N-methylcarbamoyl) adenosine 3',5'-cyclic phosphate.
 6. N⁶-(N-propylcarbamoyl) adenosine 3',5'-cyclic phosphate.
 7. N⁶-(N-phenylcarbamoyl) adenosine 3',5'-cyclic phosphate.
 8. N⁶-(ethoxycarbonyl) adenosine 3',5'-cyclic phosphate.
 9. 8-Benzylthio-N⁶-(N-phenylcarbamoyl) adenosine 3',5'-cyclic phosphate. 10.8-Benzylthio-2'-O-butyryl-N⁶ -(N-phenylcarbamoyl) adenosine 3',5'-cyclicphosphate.
 11. 2'-O-butyryl-N⁶ -(N-phenylcarbamoyl) adenosine3',5'-cyclic phosphate.
 12. A compound of the formula ##STR4## wherein Yis selected from the group consisting of COOR₁, CONHR₁ and CONHC₆ H₅ ; Xis selected from the group consisting of COOR₁, CONHR₁, CONHC₆ H₅, C₁-C₄ acyl and H and R₁ is lower alkyl.
 13. A compound according to claim12 wherein X is acyl or H.
 14. A compound according to claim 12 whereinX is H.
 15. A compound according to claim 13 wherein Y is CONHR₁.
 16. Acompound according to claim 13 wherein Y is CONHC₆ H₅.
 17. A compoundaccording to claim 15 wherein R₁ is C₁ -C₃ alkyl.
 18. A compoundaccording to claim 16 wherein R₁ is C₁ -C₃ alkyl.
 19. A compoundaccording to claim 14 wherein Y is CONHR₁.
 20. A compound according toclaim 14 wherein Y is CONHC₆ H₅.
 21. A compound according to claim 15wherein R₁ is C₁ -C₃ alkyl.
 22. A compound according to claim 16 whereinR₁ is C₁ -C₃ alkyl.